In the manufacturing process of a semiconductor device, various films are formed on a semiconductor wafer (hereinafter, referred to as a wafer), which is a substrate. One of these films may be used as a mask for processing a lower layer film thereof. Since a specific example will be given in the detailed description of the invention, it will be briefly described here. In some cases, it is required to form a film of a specific material in order for the film to function as a mask. However, since the wafer tends to warp due to the characteristics of the film, it is difficult to perform fine processing on the film, thereby hindering the micronization of the wiring.
The prior art discloses a technique in which PMMA (acrylic resin) is previously filled in the hole of a porous low-permittivity film on the substrate, a process such as an etching processing is performed with respect to the low-permittivity film, the substrate is heated, a solvent is supplied, and the PMMA is removed by radiating microwaves thereto. However, this technique cannot solve the above problem.